An Extinction Rebellion demonstrator who scaled Big Ben is now in custody after evading police for more than three hours.
Tree surgeon Ben Atkinson, 43, climbed the scaffolding surrounding Big Ben dressed as Boris Johnson - complete with a blonde wig, shirt, jacket and tie - at around 3.30pm on Friday.
Mr Atkinson, from Rydal in Cumbria, avoided police who had ascended the structure via the builders' lift by unclipping his harness and sitting on a girder.
He was eventually detained at around 6.45pm.
The group said Mr Atkinson would be displaying an Extinction Rebellion banner from the tower - currently under maintenance and surrounded by scaffolding - to "highlight Government inaction on the climate and ecological emergency".
The demonstrator - who appeared to be wearing a costume and wig mimicking Prime Minister Boris Johnson - unfurled a flag and waved to the crowds below.
One sign showed the Extinction Rebellion logo and the words "No pride on a dead planet" another said: "Citizens Assembly".
Explaining his motive in a Facebook post, Mr Atkinson wrote: "Gone and done it... Extinction Rebellion. Here to stay."
"We got the declaration of climate emergency last time. Now perhaps, please Boris, you're struggling to navigate Brexit let alone work our way out of the sixth mass extinction event. Please. Pretty please.... let's get on with the citizens assembly. Thank's Boris.
"I know somewhere in there you have compassionate feelings towards something other then your career. You've got Premiership. Now you've got a chance to do something that could last for centuries. A legacy of being the man that turned it all around. Dare you.
"Oh, and thanks Greta. I heard you calling."
Police have asked people to leave the area directly in front of the protester, and closed an entrance to Westminster tube station.
A spokeswoman for the Met Police said the force had officers at the scene, but declined to comment on how they were planning on getting Mr Atkinson down.